Polytetrafluoroethylene—hereinafter abbreviated to “PTFE”—is a material having excellent suitability for electrical applications. It has a low dielectric constant and a low dissipation factor. The dielectric properties can be further improved if the PTFE is foamed. Even at high temperatures, this material is stable and does not burn, and it can therefore in principle be used not only for electrical purposes but in all fields of engineering.
Known techniques for processing this material, which is therefore suitable for a wide variety of applications, are restricted to what is known as paste extrusion or ram extrusion. For this, the PTFE in powder form is charged to a paste extruder and compressed by means of a ram into an attached mould. This also applies to the PTFE foam produced according to DE 100 03 587 A1, mentioned in the introduction. To produce this, a foam-former having chemical action is admixed with the PTFE powder, and the material is foamed in the finished moulding by supplying an appropriate amount of heat, during a sintering procedure. Production of this type of moulding is therefore relatively complicated. There is moreover a restriction on the length of mouldings that can be produced in this way.